1. Field of the Invention
This invention relates to a semiconductor integrated circuit device and a programming method thereof and is-applied to a semiconductor integrated circuit device having a NAND flash memory, for example.
2. Description of the Related Art
Conventionally, high voltage is applied to high-voltage transistors such as transfer transistors arranged in the row decoder of a NAND flash memory, for example. High voltage (Vpgm+Vth, Vpgm or the like) necessary to transfer so-called program voltage Vpgm to a selected word line is applied to the control gate of the transfer transistor.
For example, in Jpn. Pat. Appln. KOKAI Publication No. H10-302488, an example in which program voltage Vpgm is transferred to the control gate by use of the high-voltage transistor is disclosed. Recently, the voltage value of the program voltage tends to increase with an increase in the number of memory cells.
Further, since the voltage value of the program voltage is approximately 18V and extremely high, for example, there is a tendency that the gate insulating film is destroyed and so-called field inversion occurs via an element isolation insulating film between adjacent high-voltage transistors. Therefore, it is necessary to make the film thickness of the gate insulating film larger and increase the distance between the adjacent high-voltage transistors.
As a result, the cell area is increased, and it becomes difficult to attain high integration density and it is disadvantageous in forming a highly fine pattern.